UC Davis on Neutering/Spaying
Updated: Dec 20, 2020
The bottom line for GOLDEN RETRIEVERS (not other breeds) is this: WAIT. Oh please, wait. While there is a marginal increase in the risk of mammary cancer in females (a highly detectable and treatable cancer), that risk is far outweighed by the benefit of having the hormones necessary to help fight the deadly cancers like hemangiosarcoma (which are difficult to detect early and for which there aren't stellar treatment options). There are strong arguments to be made for an ovary sparing spay, but if not that, at least wait until your girl is 18 months old.
For males, all of those hormones are beneficial for his whole life. If you feel you must neuter, please wait until he is at least 2 years old.
For further analysis, read this article from UC Davis: https://www.ucdavis.edu/news/golden-retriever-study-suggests-neutering-affects-dog-health/